Beer production in Nepal is a growing industry. Some local beers are now also exported, and the quality of beer has reached to quite international standards International brands are popular in the urban areas.
Cocktails can pretty much only be found in Kathmandu and Pokhara's tourist areas. There you can get watered-down "two for one drinks" at a variety of pubs, restaurants, and sports bars.
(Nepali) or chyaang (Tibetan) is a cloudy, moderately alcoholic drink sometimes called Nepali beer". While weaker than raksi, it will still have quite an effect. This is often offered to guests in Nepali homes, and is diluted with water. For your safety, be sure to ask your guests if the water has been sanitized before drinking this beverage.
Raksi is a clear liquid, similar to tequila in alcohol content. It is usually brewed "in house", resulting in a variation in its taste and strength. This is by far the least expensive drink in the country. It is often served on special occasions in small, unbaked clay cups that hold less than a shot. It works great as a mixer in juice or soda. Note that it may appear on menus as "Nepali wine".
Although not as internationally famous as Indian brands, Nepal does in fact have a large tea growing industry. Most plantations are located in the east of the country and the type of tea grown is very similar to that produced in neighboring Darjeeling. Well known varieties are Dhankuta, Illam, Jhapa, Terathhum and Panchthar (all named after their growing regions). Unfortunately over 70% of Nepal's tea is exported and the tea's you see for sale in Thamel, while they serve as token mementos, are merely the scrapings from the bottom of the barrel.
Chay is a tea drink with added milk and also sometimes containing ginger and spices such as cardamom.
Most herbal teas are made from wild flowers from the Solu Khumbu region. In Kathmandu, these teas are generally only served in high class establishments or those run by Sherpas from the Solu Khumbu.
Salty tea made with milk and butter - only available in areas inhabited by Tibetans, Sherpas and a few other Himalayan people.
Problematic due to lack of sanitary facilities and sewage treatment. It is safest to assume water is unsafe for drinking without being chemically treated or boiled, which is one reason to stick to tea or bottled water.